The present invention generally relates to apparatus for mounting electrical conductors to utility poles, and more particularly to adapters permitting multiple circuits to be mounted to a single utility pole.
A common overhead electrical distribution system generally operates in one of two ways: either in an arrangement known as a "grounded wye system" or in a "delta system." In both systems, three primary conductors, normally copper or aluminum cables, operate at voltages 120 degrees out of phase with one another (commonly referred to as a "3-phase system"). The voltage travels out from a source (typically a "sub-station") through the primary conductors and then returns to the source. In the grounded wye system, the voltage returns to the source through a neutral (grounded) conductor, while in the delta system, it returns through one of the three primary conductors.
The three conductors are typically mounted to utility poles by either candlestick or cross-arm type construction. In cross-arm type construction, a pair of arms are mounted in transversely extending relation to a utility pole, adjacent the upper end thereof, and in spaced, parallel relation to one another. Three insulating devices are mounted to the pole and cross-arm; one insulator mounted adjacent each end of the cross-arm, and one mounted to the pole, in vertically spaced relation to the cross-arm. Each of the three conductors are mounted to separate insulators, thereby creating a 3-phase system.
Although use of a three phase system is common, and has been for a long period of time, utility companies are beginning to experience increased usage of electricity, thereby creating circuit overload problems in the systems. To accommodate the increased loads on the electrical conductors, the simple solution is to run additional lines from the sub-station. While effective at handling increased loads, this solution is difficult, time consuming and expensive due to the minimum space available on utility poles having cross-arm or candlestick type constructions. In order to maintain the legally required spacing between electrical cables and tele-communication cables, and prevent electrical interference with the multiple circuit mounted on the poles, the original circuit layout on the poles has to be entirely redone, or additional poles need to be run to support the additional circuits.
It is therefore a principal object and advantage of the present invention to provide an adapter that facilitates mounting a plurality of 3-phase circuits to a single utility pole using a combination of candlestick and cross-arm construction.
It is another object and advantage of the present invention to provide an adapter that may be used on cross-arm constructions of mounted to poles of various diameters.
It is a further object and advantage of the present invention to provide an adapter that is easily and inexpensively manufactured.
It is yet an additional object and advantage of the present invention to provide an adapter that is easy to install on existing utility poles.
Other objects and advantages of the present invention will in part be obvious and in part appear hereinafter.